Meat in the U.S. may be widely contaminated with strains of drug-resistant bacteria, researchers reported Friday.
Nearly half of all meat and poultry sampled in a new study contained drug-resistant strains of Staphylococcus aureus, the type of bacteria that most commonly causes staph infections. Such infections can take many forms, from a minor rash to pneumonia or sepsis. But the findings are less about direct threats to humans than they are about the risks of using antibiotics in agriculture.
Researchers from the Translational Genomics Research Institute, a nonprofit biomedical research center in Phoenix, analyzed 136 samples of beef, chicken, pork and turkey from 80 brands. The samples came from 26 grocery stores in five cities: Los Angeles, Chicago, Fort Lauderdale, Fla., Flagstaff, Ariz., and Washington, D.C.
About half — 47% of the samples — contained S. aureus, the researchers reported Friday in Clinical Infectious Diseases. Of those bacteria, 52% were resistant to at least three classes of antibiotics. DNA testing suggested the animals were the source of contamination. The research was funded by the Pew Campaign on Human Health and Industrial Farming.
"The fact that drug-resistant S. aureus was so prevalent, and likely came from the food animals themselves, is troubling, and demands attention to how antibiotics are used in food-animal production today," said Lance Price, lead author of the study and director of TGen's Center for Food Microbiology and Environmental Health, said in a news release.
Antibiotics are routinely given to livestock to promote growth and prevent disease in crowded pens. Last summer, the Food and Drug Administration urged the meat industry to cut back on antibiotics use over concerns that the bacterial resistance bred in stockyards makes antibiotics less effective in humans.
About 11,000 people die every year from S. aureus infections, according to the Centers for Disease Control and Prevention, and more than half of those deaths are from the hospital “superbug” methicillin-resistant S. aureus (MRSA).
The direct risk to meat consumers – a staph infection from the meat — can be reduced by cooking meat thoroughly and washing all foods or surfaces that come in contact with raw meat. But the wider danger is to public health—that antibiotics will become increasingly ineffective in humans.